1. Field of the Invention
The present invention relates generally to a method and system for recycling paper products and other recyclable cellulosic materials, and more specifically to a method and system for producing stabilized pest control insulation from waste paper products such as old newsprint, by shredding and fiberizing the waste paper stock and then treating the fiberized paper with additives which may include: pesticides such as boric acid, dust inhibitors, fire retardants and other materials, depending upon the specific application and desired characteristics of the final EPA Registerable Pest Control product.
2. Description of Related Art
Discarded paper products make up approximately thirty-eight percent of the total waste stream. With available landfill space decreasing, recycling of paper products has become necessary. It has been found that a variety of useful products may be manufactured from recycled paper products. This has the dual benefit of reducing the volume of waste, which must be landfilled, and enabling the production of a variety of useful materials at a relatively low raw material cost.
Paper waste, such as old newsprint, can be recycled by known recycling techniques to produce a variety of products, including building insulation, animal bedding, soil amendment mulch, spill absorbents, boiler fuel pellets and packaging materials.
Low-density cellulose insulation can be made from paper fibers obtained from most types of bulk waste paper stock. The most common type of bulk waste paper stock used for insulation is old newsprint. To make cellulose insulation from newsprint, the newsprint is shredded, and then fiberized after being mixed with, for example, a fire retardant chemical. Air cells within the shredded paper make the product lightweight and provide the thermal resistance necessary to make a high quality building insulation. Other chemical additives may be introduced to the insulation product, such as pesticides, moisture and dust inhibitors, stabilizers, fragrances and colorants.
Waste paper stock can also be recycled to produce soil amendment mulch for soil conditioning, erosion control or seedling protection. The paper is shredded or chipped, and additives are introduced to fertilize the soil, resist or accelerate decomposition, provide products of different colors and provide pesticides.
Waste paper can also be recycled to produce a spill absorbent material for cleaning up liquid spills. Additives can be provided to spill absorbents which improve the absorbency of the product, resist flammability and neutralize a variety of chemicals. Boiler fuel pellets and packing materials can also be produced from recycled paper waste.
Because of the different characteristics required for each application, the methods of producing each of these products vary greatly, as do the products themselves. For example, a variety of additives can be provided along with the recycled paper base material to impart characteristics desirable for the specific application.
In the field of cellulose insulation, for example, it has been found desirable to introduce additives including pesticides, dust inhibitors, fire retardants and stabilizers. At proper dosage levels, pesticides such as boric acid help control and kill many self-grooming insects such as termites, cockroaches, ants, silverfish, earwigs, crickets, Darkling Beetles and booklice. Cellulose insulation with the added benefit of such pest control can prevent infestation of certain insects. Insulation with pest control is a long-lasting alternative that adds value to the structure, and comfort to those that dwell in the structure.
Conventional insulation typically incorporates heavy chemical loading (a minimum of 25 percent) in order to provide limited pest control properties. Yet, the result of such heavy loading is less fiber to insulate, and more dust with which the applicator must deal.
Thus, a need exists for a method and system of providing insulation from recycled paper that provides permanent pest control benefits without the loss of R-value or coverage. It would be beneficial to reduce the chemical loading of conventional insulation by approximately 50%. It would further be beneficial to add a liquid to the insulation that would greatly reduce nuisance dust. Further, it would be beneficial to add a stabilizer so that the insulation will not unduly settle.
It is desirable that a xe2x80x9cready-to-usexe2x80x9d insulation be provided that has the advantages of other cellulose insulation with pest control protection, but without the known deficiencies in coverage and an abundance of dust that currently plague conventional cellulose insulation.
Simply adding borates to insulation is known, but disadvantageous for a number of reasons. For example, U.S. Pat. No. 4,454,992 to Draganov discloses a wet process apparatus for rendering cellulosic insulation particles fire retardant by impregnating the insulation material with an aqueous solution of a non-hygroscopic fire retardant composition and then maintaining the insulation material in a hot and humid atmosphere for a prolonged period of time prior to drying. The Draganov apparatus comprises: (1) a grinding mill to grind cellulosic insulation; (2) spray nozzles to spray the insulation with water; (3) hot vapor in a humidifying conduit to humidify the wetted insulation; (4) a conditioning bin in which the insulation remains from at least 10 minutes to more than an hour at temperatures from 140 to 190 degrees F.; and (5) a dryer to dry the conditioned insulation. Further, Draganov teaches the application of boric acid to waste paper immediately after grinding. xe2x80x9cIt is applied to the waste paper either dry during the grinding operation or immediately thereafter in aqueous solution . . . xe2x80x9d Col. 3, lines 5-6.
It would be beneficial to provide the liquid additive either during fiberizing, or after such fiberizing. Yet, this is contrary from the teaching of Draganov that boric acid in liquid form be added immediately after grinding. Adding borates to insulation with a liquid additive to aid the borates absorb into the paper, to inhibit dust, and to stabilize the insulation, is believed novel.
Present cellulose insulation products are known to contain borates, but not of sufficient quantities to provide effective insect control. The only cellulose product that does have sufficient borates to qualify as an EPA Registered Product (InCide), lacks the process of liquid additives that impart stability, increase coverage, and reduce dustxe2x80x94important considerations for building owners and insulation contractors.
Other types of cellulose products provide animal bedding. Animal bedding with pesticides and disease immune additives protects the health of the animals using the bedding. Ammonia inhibitors can be added to the animal bedding to help control fumes and odors caused by animal waste, thereby reducing the ventilation necessary. This reduces the expense of electricity used to run the ventilating fans in the animal pens, and also reduces heating expenses, as less heat is lost through the ventilation exhaust. It has been found desirable to provide a bedding material having higher thermal insulative properties than known bedding materials, thereby also helping to reduce heating expenses.
Known bedding materials and known methods of producing these materials have been found to be less than adequate in use. For example, commonly used bedding materials such as wood shavings and sawdust do not provide good thermal insulation, and are flammable. Also, these materials are increasingly used for other applications, such as producing xe2x80x9cparticle boardxe2x80x9d building materials, fuels, and for other uses. This has resulted in increased costs and decreased availability.
These known bedding materials also lack the pesticidal, disease-inhibiting and ammonia-inhibiting characteristics which have been found desirable, and may, in fact, promote the proliferation of pests and disease. In the past, in order to provide known bedding materials such as wood shavings and sawdust with pesticidal and disease inhibiting qualities, it has been necessary to first lay down the bedding material, next spray the bedding with a medicinal disease inhibitor, and finally, spread a pesticide over the bedding. This three step process is labor-intensive and results in substantial down-time for the facility.
Previous attempts to use recycled paper waste as a pest control insulation, and as an animal bedding, and have proved less than successful. Simple shredded paper with borate additives have has been found to be less than entirely satisfactory as an construction grade insulation product as it is dusty, has poor coverage and lacks a stabilizer to bind the insulation in place. This is primarily due to the lack of a liquid additive to help the borates adhere to the paper and a stabilizer (starch adhesive) for stability and dust-reduction. It has also been found that chemical additives do not adhere to the surfaces of dry shredded paper as well as would be desired. and that the material does not decompose as readily as would be desired. Further, shredded paper tends to compress, or lie flat when used. Because normal shredded paper does not xe2x80x9cloft,xe2x80x9d it does not provide good surface coverage (i.e., low surface area covered per unit weight).
Thus, it has been found that a need exists a cellulose insulation with pest control protection, and a method for making same, which enables the addition of various additives to the recycled paper product, thereby permitting the product""s characteristics to meet a variety of requirements.
For example, it has been found that a need exists for a method and system for producing pest control insulation with additives to provide fire resistance, insect control to help control insects and rodents, dust control to reduce dust during application and a stabilizer to reduce settling. It is also desirable that a xe2x80x9cready-to-usexe2x80x9d insulative material be provided, thereby eliminating labor-intensive insulation treatment procedures and their inherent facility down time.
There also exists a need for a method and system capable of applying a sufficient quantity of additives to a paper base material in a manner which causes the additives to adhere to the base material.
A need further exists for a method and system of producing a pest control insulation material having good thermal insulating qualities, high absorbency excellent acoustical properties, high surface coverage per unit weight, and high loft (stabilization) in use.
A need also exists for an economical method and system for making a pest control insulation and an animal bedding material meeting these needs from readily available waste products, thereby reducing the amount of waste to be landfilled.
It is to the provision of a method and system meeting these and other needs that the present invention is directed.
Briefly described, in a preferred form, the present invention comprises a cellulose insulation with pest control protection (stabilized pest control insulation) and a method and system for producing such insulation from cellulosic waste products, such as paper, paper sludge, peanut hulls, wood shavings (green or dry), rice hulls and straw at a greatly reduced dry chemical loading rate to known applications. The preferred base material is recycled paper waste, such as old newsprint. A stabilized pest control insulation will be understood to be an insulation wherein one or more additives is applied to the stabilized pest control insulation""s base material in a specified quantity and manner, so as to impart the insulation material with certain desired characteristics. The stabilized pest control insulation can be used for structures to provide insulative qualities to the structure, or in other applications such as animal bedding.
The preferred form of the system and method of the present application uses mechanical and pneumatic material handling equipment to move waste paper stock from one process machine to the next. The process machines comprise a primary grinder, a fiberizer and a moiler. Various other components can be included to produce a more effective and marketable product.
The process of producing the stabilized cellulose insulation with pest control protection begins with dumping waste paper stock onto a charge conveyor. A metal detector is provided along the path of the conveyor to help prevent metal from entering the system. The waste paper travels along the conveyor and drops into a primary grinder. The primary grinder reduces the size of the waste paper stock to paper chips. A primary transfer blower pulls the paper chips away from the grinder and into a cyclone separator. The cyclone separates the paper chips from the air stream and directs them into a fiberizer tank.
Typically, the air stream from which the paper chips have been removed continues on from the cyclone to a dust collector. Screw feeders in the fiberizer surge tank, and a second separate air stream, meter and direct the paper chips out of the surge tank into a fiberizer.
The fiberizer is a size-reduction process machine which receives the paper chips from the surge tank and grinds the relatively large chips into very small paper fibers. Because the paper is reduced to a xe2x80x9cfiberizedxe2x80x9d state, rather than simply shredded, more surface area is exposed, and the material is fluffier than ordinary shredded paper. This gives the material greater loft and surface coverage, better absorbency, and better thermal insulative qualities than ordinary shredded paper.
A dry chemical additive may be provided to the fiberized material through a chemical mixer/hopper connected to the fiberizer. The chemical mixer can include a chemical feeder, which meters and feeds the additive to a pulverizer. The pulverizer grinds solid chemical additives and blows the additives into the inlet of the fiberizer. Because the material is fiberized, rather than simply shredded, more surface area is exposed on which the additive may attach. Thus, increased additive-to-base material ratios can be achieved.
A secondary transfer blower helps to pull the paper chips from the fiberizer surge tank and the chemical additive from the pulverizer through the fiberizer, and through a moiler located downstream from the fiberizer. The moiler is an in-line process device that introduces an atomized mist of liquid additives into the paper fibers. These liquid additives can include pesticides, disease immune additives (medicines), ammonia and dust inhibitors, fire retardants, stabilizers, and other additives, depending on the desired characteristics of the final pest control product. It has been found that the introduction of liquid additives through the moiler promotes greater adherence of dry additives to the base material, thereby enabling higher additive-to-base material ratios and more accurate control of the mixture.
After the introduction of liquid additives in the moiler, the product is ready for packaging. A diverter valve can be installed at the moiler outlet to allow the product to be discharged to either a bulk discharge system or a baler.
The present invention preferably incorporate two steps to produce cellulosic fibers. The present process includes that cellulosic waste product if first ground to form cellulosic chips, and then the cellulosic chips are fiberized to form cellulosic fibers, wherein these two steps are independent from one another. Several benefits are gained by such a two-step process as disclosed in the present application. For example, a surge protector can be placed between these two steps. Second, a dust removal step may be introduced between these two steps.
The present invention further preferably utilizes a non-slurry application of the liquid additive (in atomized form and/or through a moiler), as the preparation of a slurry bath necessitates the addition of a drying unit.
Accordingly, it is an object of the present invention to provide a stabilized pest control insulation building material and a method for producing it from a recycled cellulosic material such as waste paper, and permitting the addition of a variety of specialized additives, in either liquid or solid form, to achieve an EPA Registered final pest control product.